Siegler Sorin, Caravaggi Paolo, Tangorra James, Milone Mary, Namani Ramya, Marchetto Paul A
Department of Mechanical Engineering, Drexel University, Philadelphia, PA, USA.
Movement Analysis Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy.
J Biomech. 2015 Oct 15;48(13):3650-5. doi: 10.1016/j.jbiomech.2015.08.014. Epub 2015 Aug 20.
The posture of the head and neck is critical for predicting and assessing the risk of injury during high accelerations, such as those arising during motor accidents or in collision sports. Current knowledge suggests that the head's range-of-motion (ROM) and the torque-generating capability of neck muscles are both dependent and affected by head posture. A deeper understanding of the relationship between head posture, ROM and maximum torque-generating capability of neck muscles may help assess the risk of injury and develop means to reduce such risks. The aim of this study was to use a previously-validated device, known as Neck Flexibility Tester, to quantify the effects of head's posture on the available ROM and torque-generating capability of neck muscles. Ten young asymptomatic volunteers were enrolled in the study. The tri-axial orientation of the subjects' head was controlled via the Neck Flexibility Tester device. The head ROM was measured for each flexed, extended, axially rotated, and laterally bent head's orientation and compared to that in unconstrained neutral posture. Similarly, the torque applied about the three anatomical axes during Isometric Maximum Voluntary Contraction (IMVC) of the neck muscles was measured in six head's postures and compared to that in fully-constrained neutral posture. The further from neutral the neck posture was the larger the decrease in ROM and IMVC. Head extension and combined two-plane rotations postures, such as extension with lateral bending, produced the largest decreases in ROM and IMVC, thus suggesting that these postures pose the highest potential risk for injury.
头部和颈部的姿势对于预测和评估在高加速度情况下（如在汽车事故或碰撞性运动中出现的情况）的受伤风险至关重要。目前的知识表明，头部的活动范围（ROM）和颈部肌肉产生扭矩的能力既相互依赖又受头部姿势的影响。对头部姿势、ROM和颈部肌肉最大扭矩产生能力之间关系的更深入理解，可能有助于评估受伤风险并开发降低此类风险的方法。本研究的目的是使用一种先前经过验证的设备，即颈部柔韧性测试仪，来量化头部姿势对颈部肌肉可用ROM和扭矩产生能力的影响。十名年轻无症状志愿者参与了该研究。受试者头部的三轴方向通过颈部柔韧性测试仪设备进行控制。针对每个头部弯曲、伸展、轴向旋转和侧向弯曲的方向测量头部ROM，并与无约束中立姿势下的ROM进行比较。同样，在六种头部姿势下测量颈部肌肉等长最大自主收缩（IMVC）期间围绕三个解剖轴施加的扭矩，并与完全约束中立姿势下的扭矩进行比较。颈部姿势离中立位置越远，ROM和IMVC的下降就越大。头部伸展以及两个平面的联合旋转姿势，如伸展并侧向弯曲，导致ROM和IMVC下降最大，因此表明这些姿势造成受伤的潜在风险最高。
